Heretofore, self propelled apparatus has been provided, such as shown in U.S. Pat. No. 4,603,516 for cleaning the outside of pipe as the apparatus moves along a pipeline while supported thereon. Cleaning the outside of pipe removes loose rust, scale and dirt, to prepare the pipe for the subsequent application of a coating material on the outer surface of the pipe to minimize corrosion and prolong the service life of the pipe. In some instances, the pipe may be wrapped with an outer lining material containing an inner coating material for contacting the outer cleaned surface of the pipe. Normally abrasive particles, such as hard shot particles or grit, have been thrown by centrifugal force from an impeller wheel or the like against the outside of the pipe for cleaning the pipe. Particularly where hard shot particles of a uniform size were used previously, a relatively smooth clean outer surface of pipe was provided.
Oftentimes, a pipe coating removal device utilizing high pressure water is provided ahead of the so-called de-scaling apparatus so that the pipe coating, such as a bituminous layer, is first removed before the de-scaling operation by a separate cleaning device. For example, as shown in U.S. Pat. No. 4,552,594 dated Nov. 12, 1985, a carriage travelling along a pipeline discharges high pressure water from water jets or nozzles for removal of an outer coating on the pipe. The nozzles are positioned about the pipe for oscillation as the apparatus moves along the pipe thereby to clean the entire outer periphery of the pipe. An enclosed chamber or housing is normally provided on a travelling carriage of the pipe cleaning apparatus for maintaining the discharge water or grit in an enclosed volume about the pipe.
In the past, many pipelines were coated with materials that are not acceptable environmentally, such as coatings containing various percentages of certain materials, such as asbestos, fiberglass, or bituminous materials. Such materials must be disposed of in an approved manner, such as an approved remote disposal site. For this purpose, some provision must be made to collect the waste material from the cleaning or coating operation for removal to the remote disposal site.